A 2×27.5 kV AT power supply method is mainly used for a traction power supply system in an electrified railway, such as high speed railways at home and abroad, passenger dedicated lines, heavy haul railways and so on, to meet the traction electricity requirement of an electric locomotive. The traction power supply system of the AT power supply method mainly consists of a traction substation, a section post, an AT post and a traction network. The parallel power supply method, in which the AT post is passed through the middle of a feeder and the section post is passed through the end thereof, is adopted (referring to FIG. 1 in details). The traction network of the method has the advantages of small impedance, the reduction for voltage loss of the traction network and the improvement for power supply quality. An indoor GIS inflatable switchgear is mainly adopted in 2×27.5 kV equipment of each post. Sometimes an indoor grid spacing location method is adopted in the equipment.
1. The Prior AT Post
(1) Main Connection Lines of the Prior AT Post
FIG. 2 shows the main connection lines of the prior AT in details.
In the prior AT post, H1˜H5 are GIS inflatable switchgears. AT1 and AT2 are autotransformers.
In the normal operation, a circuit breaker IDL in H1 and a disconnector 1G therein are closed. A circuit breaker 2DL in H2 and a disconnector 2G therein are closed. Parallel power supply in the middle of a feeder is realized through 1DL and 1G as well as 2DL and 2G by an upper/a down line traction network supplied with power by a first traction substation. When the upper/the down line traction network has fault, 1DL and 2DL have no a time-delay opening switch and the switch of a circuit breaker of feed lines of the traction substation is opened; therefore, the fault is cleared. After the fault is cleared, an auto-reclosing of the circuit breaker of the traction substation is initialized to be closed and supplies power to the traction network again. If the fault is not permanent, 1DL and 2DL are respectively detected to be the closing switch with voltage, and parallel power supply is recovered. If the fault is permanent, the switch is opened in acceleration behind the circuit breaker of feed lines of the traction substation, and then the fault circuit is cut. Meanwhile, 1DL and 2DL continue to be kept in opening state of the switch. After the fault circuit is recovered to be normal, the 1DL and 2DL are respectively closed and the parallel power supply is recovered.
A circuit breaker 3DL in H3, a disconnector 3G therein and an autotransformer AT1 therein as well as a circuit breaker 4DL in H4, a disconnector 4G therein and an autotransformer AT2 therein are blocked with each other. They can not be operated at the same time and are fixed backups with each other. In normal operation, the switches of 3D and 3G are closed, and AT1 is carried with current. When AT1 has fault, 3DL is opened; AT1 is out of service; a spare device is initialized; the switches of 4D and 4G are closed automatically, and AT2 is operated.
Therefore, when being in normal operation, the operation methods between H1 and H2 as well as H3 and H4 have no direct electric link. Actually, they can be divided into a parallel power supply unit consisting of 1DL, 1G, 2DL and 2G. An independent AT post consisting of 3DL, 3G, AT1, 4DL, 4G and AT2 functions as parallel power supply and the AT post. Therefore, the AT post can be regarded as an electric facility combined by a parallel power supply unit and an improved AT together. Hence, with actual construction demand and product manufacture, the parallel power supply unit is designed as a modularized electric apparatus which can be located beside a main line of railway, does not need special area, is located at the same longitudinal axis of a strut of a contact network and meets side clearance requirements. The improved AT post is designed as an integrated electric apparatus with small occupation area, independence and commonality. The abovementioned apparatuses are all manufactured in factory, which can reduce on-site construction quantity, shortens construction period as well as save land resources and construction investment.
(2) The Location Method of the General Layout Plan of the Prior at Post
FIG. 3 shows the location method of the general layout plan of the prior AT post in details.
The prior AT post consists of the apparatuses in indoor and outdoor parts, wherein autotransformers AT1 and AT2 are located outdoors, other apparatuses are located indoors with the adoption switchgear method. A cable assess method is adopted for all of 27.5 kV inlet and outlet wire. In order to meet the location requirements of the apparatuses, the main manufacture houses, such as a high-voltage room, a secondary apparatus room (which is used for the location of an AC power supply panel and a DC power supply panel, an integrated automation system panel, a video monitor screen, etc.), a communication room, a tool room and so on, must be equipped. Meanwhile, as there are relatively many high-voltage cables of the inlet and outlet wires, a cable interlayer is needed to be arranged under the manufacture houses to meet the requirements of the laying of the cables. Although the AT post of this type have full functions, a field with the area of about 20×40 m2 near the place at which the AT post is needed to be arranged must be selected according to the location requirements of all of the apparatuses and the manufacture houses, which results in the increase of difficulty of site selection. Meanwhile, relatively much investment in the manufacture houses and 27.5 kV connection cables among four-circle 27.5 kV cable inlet and outlet wire, four-circle switchgear and the AT is also required.
2. The Prior Section Post
(1) FIG. 4 shows the main connection lines of the prior section post in details.
When being in normal operation, a disconnector 11G in H1 and a disconnector 21G therein are opened. A circuit breaker 1DL in H11 and a disconnector 1G therein are closed. A circuit breaker 3DL in H3 and a disconnector 3G therein are closed. Parallel power supply at the terminal of the a feeder is realized through 1DL and 1G as well as 3DL and 3G by an upper and a down traction network of which power is supplied by a first traction substation. When the upper (or down) traction network has fault, 1DL and 3DL have no time-delay opening; A circuit breaker of feed lines of a traction substation is opened, and the fault is cleared. After the fault is cleared, an auto-reclosing of the circuit breaker of the feed line of the traction substation is initialized to be closed and supplies power to a traction network. If the fault is not permanent, 1DL and 3DL are respectively detected to be in voltage closing, and parallel power supply is recovered. If the fault is permanent, the switch is opened in acceleration behind the circuit breaker of feed lines of the traction substation, and then a fault circuit is cut. At this time, 1DL and 2DL continue to be kept in opening state and are respectively closed after a fault circuit is recovered and normal; hence parallel power supply is recovered. Similarly, 2DL and 2G in H2 as well as 4DL and 4G therein are closed. Parallel power supply at the end of a feeder is realized through 2DL and 2G as well as 4DL and 4G by an upper/a down traction network of which power is supplied by a second traction substation.
A circuit breaker 5DL in H5, a disconnector 5G therein and an autotransformer AT1 therein as well as a circuit breaker 7DL in H7, a disconnector 7G therein and an autotransformer AT2 therein are blocked with each other. They can not be operated at the same time and are fixed backups with each other. When being in normal operation, 5DL and 5G are closed, and AT1 is carried with current. When AT1 has fault, 5DL is opened; AT1 is out of service, a spare device is initialized; 7DL and 7G are automatically closed, and AT2 is put into operation. Similarly, AT3 and AT4 can not be put into operation at the same time and are fixed backups with each other.
When a first traction substation is out of service because of fault, a disconnector 11G in H1 and a disconnector 21G in H2 are closed. Over-zone power supply is offered to an upper and a down traction network of the first traction substation through 11G and 21G by a second traction substation. On the contrary, when the second traction substation has fault, over-zone power supply is also realized for the first traction substation through 11G and 21G.
Therefore, H1, H3, H5, H7, AT1 and AT2 as well as H2, H4, H6, H8, AT3 and AT4 are respectively formed into two of the prior AT posts. When being in normal operation, their operation methods have no direct electric link. Only when over-zone power supply is needed, they are linked together through disconnectores 11G and 21G to realize over-zone power supply function. Therefore, it can be regarded that the prior section post consists of two of the prior AT posts and an over-zone power supply disconnector.
Through the functional analysis for the prior section post and AT post, the prior section post can be regarded as one electric facility is assembled through guide lines by two independent parallel power supply units, two independent integration AT posts and two independent over-zone power supply units. Therefore, with the combination of actual construction demands and product manufacturing, the parallel power supply and the over-zone power supply unit are respectively designed as one independent modularized electric apparatus which can be located beside a main line of railway, does not need special area, and is located at the same longitudinal axis of a strut of a contact network and meets side clearance requirements. An integrated AT post is designed as an integrated electric apparatus with relatively small occupation area, independence and commonality. The integrated electric apparatus are mainly manufactured in the factory, which can reduce on-site construction quantity, shorten construction period, save land resources save construction investment.
(2) The Location Method of the General Layout Plan of the Prior Section Post
FIG. 5 shows the details of the location of the general layout plan of the prior section post in details.
The prior section post consists of indoor and outdoor apparatuses, wherein autotransformers AT1˜AT4 are located outdoors. Other apparatuses are located indoors with the adoption of a switchgear method. A cable inlet and outlet method is adopted for all of 27.5 kV inlet and outlet wire. In order to meet the location requirements of the apparatuses, main manufacture houses, such as a high-voltage room, a secondary apparatus room (which is used for the location of an AC power supply panel and a DC power supply panel, an integrated automation system panel, a video monitor screen, etc.), must be equipped. At the same time, as there are relatively many the high-voltage cable of the inlet and outlet wires, a cable interlayer is arranged under the manufacture houses to meet the requirements of the laying of the cables. Although a section post of this type has full functions, a field with the area of about 30×40 m2 near a bus station equipped with a neutral section insulator must be selected to meet the requirements of the location of the section post, which results in the increase of difficulty. At the same time, relatively much investment in the manufacture houses and 27.5 kV connection cables among eight-circle 27.5 kV cable inlet and outlet wire, an eight-circle switchgear and the AT is also required.
3. The Prior Traction Substation
FIG. 6 shows the main connection lines of the prior traction substation in details.
As for main apparatuses such as a 2×27.5 kV circuit breaker of the prior traction transformer, a voltage transformer, a current transformer and a disconnector, except the disconnector of feed lines and a thunder resistance circle which are located outdoors, others are located indoors with the adoption of a GIS inflatable switchgear and can meet the use requirements of products only when they are equipped with manufacture houses. A cable inlet and outlet method is adopted for all of high-voltage 27.5 kV inlet and outlet wire. As there are relatively many high-voltage cables of inlet and outlet wire, a cable interlay is needed to be arranged under the manufacture houses to meet the requirements of the laying of the cables. Although this location method has relatively high reliability of power supply, relatively much investment in land acquisition, manufacture houses, a GIS inflatable switchgear and a 27.5 kV cable is required.
4. The Current Manufacture Situation of 2×27.5 kV Apparatuses at Home and Abroad
Currently, a GIS method that SF6 gas is filled in a 2×27.5 kV switchgear used in a traction substation, a section post and an AT post which are of an AT power supply method of a traction power supply system in the prior an electrified railway at home and abroad is mainly adopted. In order that the SF6 gas is prevented from escaping and polluting environment in use process, a large quantity of measures are taken in the manufacturing process of products, which results in very high manufacturing cost of the products and relatively huge construction investment. As for a 2×27.5 kV air-insulation switchgear, in order that the requirement of electrical safety distance is met, the outline dimension of the products becomes too big and a relatively big field and manufacture houses are needed. When an indoor grid spacing method is adopted, bigger field and bigger manufacture house are needed. Although apparatuses such as a 2×27.5 kV outdoor circuit breaker, a voltage transformer, a current transformer, a disconnector and so on are adopted too, a relatively big field is needed to meet the requirements of the installation and location of theses apparatuses when they are located outdoors as they are all single apparatuses. Furthermore, when a 2×27.5 kV outdoor independent element assembly type electric apparatus is adopted, although an outdoor location method is also adopted and house area and occupied area are decreased, the relatively big occupied area is still needed.
Therefore, a new autotransformer traction power supply system in an electrified railway is needed to replace the prior autotransformer traction power supply system in an electrified railway, wherein as for the new one, it consists of a traction substation, a parallel power supply unit, an integrated AT post, an over-zone power supply unit and a traction network; parallel power supply at the middle and the end of a feeder of an upper/a down traction network is realized through a parallel power supply unit, and over-zone power supply is realized through an over-zone power supply between two traction substations. As for the prior one, it consists of a traction substation, a section post, an AT post and a traction network, and parallel power supply is realized through the AT post at the middle of the feeder and through over-zone post at the terminal thereof. A 2×27.5 kV outdoor modularized electric apparatus is researched to meet the requirements of the new AT power supply. The prior AT section post is replaced to obtain the function of parallel power supply at the terminal of the feeder. The special area is not needed for the modularized electric apparatus, of which the installation place can be selected beside a main line of railway elastically to meet the location requirements of the outdoor traction substation. The product with the advantages of high reliability, free maintenance and miniaturization is a must. Furthermore, it is also a must to research a new integrated AT post which matches the parallel power supply unit and has the advantages of relatively small occupied area and high factory manufacture degree; furthermore, it does not need factory houses and can save land resources and the investment in cable lines. An integrated power box and a control box are used for a parallel power supply modularized electric apparatus and an over-zone power supply modularized electric apparatus. An outdoor preassembled protection measurement and control cabinet is used for an integrated AT post. An outdoor preassembled protection measurement and control cabinet is used for a traction substation. The outdoor location requirements of the modularized electric apparatus, the AT post and the traction substation must be met. The invention not only meets the requirement of safe and flexible power supplies of the AT traction power supply system in an electrified railway and that of unattended characteristics but also saves land resources, reduces the investment in factory houses and power supply lines, reduces on-site construction quantity and shortens construction period.
In the actual construction, according to the calculation requirement of traction power supply, a middle parallel power supply unit and an integrated AT post are arranged at appropriate places in the middle of a feeder; a neutral section insulator, a terminal parallel power supply unit and an integrated AT post as well as an over-zone power supply unit are arranged at the best place of terminal voltage of the feeder. As the parallel power supply unit, the over-zone power supply unit and the integrated AT post are designed and manufactured according to standards, and when being in the construction design, the parallel power supply unit and the over-zone power supply unit can be regarded as one switch apparatus in a traction network, and the integrated AT post can be regarded as one switch apparatus of the traction substation, which does not need independent design but only needs to determine their concrete installation sites; therefore, the invention has the advantages of reducing design quantity, shortening design period and increasing construction progress.